Re: [PATCH] For the `-A CMP -B -> B CMP A` pattern allow EQ/NE for all integer types

[Jeff Law via Gcc-patches]

On 6/6/23 15:07, Andrew Pinski via Gcc-patches wrote:

I noticed while looking at some code generation issue, that forwprop
was not handling `-a == 0` for unsigned types and I was confused why
it was not.
r6-1814-g66e1cacf608045 removed these from fold because they
were supposed to be already handled by the match.pd patterns
but it was missed that the match.pd patterns checked
TYPE_OVERFLOW_UNDEFINED while fold didn't do that for NE/EQ.
This patch removes the restriction on NE/EQ on TYPE_OVERFLOW_UNDEFINED.

OK? Bootstrapped and tested on x86_64-linux-gnu.

gcc/ChangeLog:

        PR tree-optimization/110134
        * match.pd (-A CMP -B -> B CMP A): Allow EQ/NE for all integer
        types.
        (-A CMP CST -> B CMP (-CST)): Likewise.

gcc/testsuite/ChangeLog:

        PR tree-optimization/110134
        * gcc.dg/tree-ssa/negneq-1.c: New test.
        * gcc.dg/tree-ssa/negneq-2.c: New test.
        * gcc.dg/tree-ssa/negneq-3.c: New test.
        * gcc.dg/tree-ssa/negneq-4.c: New test.

OK.
jeff